To J. D. Hooker 28 September 
My dear Hooker
What a good soul you are not to sneer at me, but to pat me on the back. I have greatest doubt whether I am not going to do in publishing my paper, a most ridiculous thing. It would annoy me much, but only for Murray’s sake, if the publication were a dead failure.1 I hate to hear you so falsely abuse yourself & say that you are only fit for descriptive work.2 For years & years you have been my Public & my judge, & I care more for your opinion in Nat. History, than for all the rest of the world. So do not vilify yourself;—though by Jove you cannot alter my opinion of you.—
Many thanks for list of Australian trees;3 I am so glad that you are stirring up people in this most important subject. It makes the case wonderfully odd of the S. species not having naturally spread northward.—4
It is, I believe, true that Glen Roy shelves (I remember your Indian Letters) were formed by Glacial lakes.5 I persuaded Mr Jamieson an excellent observer to go & observe them; & this is his result.—6 There are some great difficulties to be explained; but I presume this will ultimately be proved the truth. Speaking of the Australian trees reminds me that Mr Bates (who wrote so well against spreading of Lepidoptera during Glacial period)7 is going to publish his Travels with Natural Hist. notes. I heard from him a few days ago, & was so much pleased to find that he who has specially attended to the castes of neuter ants, is quite satisfied with my discussion & explanation of this most difficult case.—8 Owen sneered bitterly at what I wrote on this subject.—9
I am going to beg for help, & I will explain why I want it.—
You offer Cypripedium; I shd. be very glad of a specimen; & of any good sized Vandeæ, or indeed any Orchid; for this reason; I never thought of publishing separately & therefore did not keep specimens in spirits, & now I shd. be very glad of a few woodcuts to illustrate my few remarks on Exotic orchids.— If you can send me any, send them by Post in tin-cannister on middle of day of Saturday Oct 5th; for Sowerby will be here.—10
Secondly: have you any white & yellow vars. of Verbascum, which you could give me or propagate for me or lend me for a year. I have resolved to try Gärtners wonderfull & repeated statement, that pollen of white & yellow vars, whether used on the varieties or on distinct species has different potency.11 I do not think any experiment can be more important on Origin of species; for if he is correct, we certainly have what Huxley calls new physiological species arising.12 I shd require several species of Verbascum besides the white & yellow varieties of the same species.— It will be tiresome work, but if I can anyhow get the plants it shall be tried.
Thirdly, can you give me seeds of any Rubiaceæ of the suborder Cinchoneæ, as Spermacoce, Diodia, Mitchella, Oldenlandia.— Asa Gray says they present two forms like Primula.—13 I am sure that this subject is well worth working out. I have just almost proved a very curious case in Linum grandiflorum which presents 2 forms A & B.— Pollen of (A) is perfectly fertile on stigma of A.—
[DIAG HERE] B. A stamens stigma
But pollen of (B) is absolutely barren on its own stigma; you might as well put, so much flower on it; it astounded me to see the stigma of (B) purple with its own pollen; & then put a few grains of similarly looking pollen of (A) on them; & the germens immediately & always swelled; those not thus treated never swelling.14
Thirdly; can you give me any very hairy Saxifraga.—(for their function)
I send a resumè of my requests to save you trouble.— Nor would I ask for so much aid, if I did not think all these points well worth trying to investigate—
My dear old friend, a letter from you always does me a world of good.— And the Lord have mercy on me what I return I make—
Yours affecty. | C. Darwin
Bates agrees with CD on neuter ants.
Repeating experiment of C. F. v. Gärtner to study Huxley’s idea of physiological species.